Cold formed latch wire

ABSTRACT

A latch restraint and safety anchorage system for securing a child safety seat in an automotive vehicle behind the vehicle&#39;s seat is provided. One or more latch wires are generally mounted to a cross member of the anchorage system comprised of a pair of spatially separated legs joined at one end by a transverse latch bar. Each leg includes a tapered portion and an end portion. The end portion is exposed to allow the legs to be retained by the cross member.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a division U.S. application Ser. No. 10/602,437filed Jun. 24, 2003.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to child seat restraints for automotive vehiclesand, in particular, to a latch restraint and anchorage system forsecuring the child restraint seat to the seat of a vehicle.

2. Background Art

Child safety seats have been required for many years by law for smallchildren riding in automotive vehicles. In the past, child safety seatshave been secured to a passenger seat using standard seatbelts providedfor adult passengers that are anchored to one or more structural membersof the vehicle. The seatbelts are normally threaded through apertures orslots provided in the child safety seat secure the child safety seat inposition on the vehicle seat. The child safety seat mounting procedureis awkward and sometimes complex, which may result in impropersecurement of the child safety seat to the seat of the vehicle.

To overcome these problems, various regulations have been implementedrequiring a standardization of the structure and methods for securingthe child safety seat in an automotive vehicle. A recent Federal MotorVehicle Safety Standard (FMVSS) adopted by the National Highway TrafficSafety Administration (NHTSA) requires vehicles be equipped with childseat restraint anchorage systems. The child restraint anchorage systemoutlined in this standard, FMVSS 225, requires, in part, that loweranchorages (i.e., latch wires) be rigidly attached to the vehicle,preferably one on each side of the child seat.

U.S. Pat. No. 6,276,754 issued to Youssef-Agha, et al. discloses a childsafety seat having a pair of latch mechanisms which lockingly engage thelatch wires to secure the child safety seat in position on the seat ofthe vehicle. The Youssef-Agha child safety seat includes latch wiresthat are welded to a cross member. However, welding distorts positionand alignment of the latch wires. In other known anchorage systems forsupporting and positioning the latch wires, bent legs of each latch wireare passed through enlarged holes provided in the cross member and thensecured by a weld. The enlarged openings reduce rigidity relied upon forsupport, positioning and alignment, and make the assembly moresusceptible to deformation due to welding heat.

Still other known anchorage systems for supporting and positioning thelatch wires avoid the heat of a welding operation by providing a pair ofcollars on each latch wire leg. The legs are inserted into a crossmember up to a first collar. A second collar is formed from the portionof the legs inserted into the cross member which protrude to the otherside securing the latch wire to the cross member. This arrangement alsoavoids the need for an enlarged opening in the cross member to insertthe legs through, since the legs in this instance can be straight.However, this arrangement does not resist deformation of the latch wirecaused by use or abuse of the child safety seat as much as may benecessary.

Section S9.1 of FMVSS 225 requires the latch wire to include atransverse latch bar having approximately a 6 mm diameter. Child safetyseat latch mechanisms are designed to engage the transverse latch bar ofthe latch wire. The standard 6 mm diameter allows child safety seatmanufacturers to produce standardized latch mechanisms better equippedto safely secure a child. Further, the strength of the lower anchoragesare regulated by Section S9.4 of FMVSS 225. The standard recites themaximum allowable deflection when certain forces are applied to thelatch wire.

Typically, during manufacturing, each latch wire is formed from aconstant diameter wire form, cut and bent into its preferred shape,which generally resembles the letter “U”. The wire form is selected toensure that the transverse latch bar portion of the latch wire maintainsa constant 6 mm diameter. Thus, the remaining leg portions of the latchwire, which engage a cross member, are also approximately 6 mm indiameter. However, latch wires having such a constant diameter havedifficulty meeting the requirements for maximum allowable deflection.

Previously known systems included a support bracket placed over thelatch wire and secured to the cross member to reduce the cantilevereffect of forces on the latch wire. The support bracket avoidedmisalignment and distortion of the latch wire in anchorage systems.However, this method is problematic in that it adds an additionalcomponent increasing both the cost and assembly required.

SUMMARY OF THE INVENTION

The present invention overcomes the above disadvantages by shaping thelegs of the latch wire to provide greater strength and rigidity underbending loads. Therefore, one aspect of the present invention isdirected to an apparatus and method for providing a restraint anchoragefor a child restraint system. As described in greater detail below, theapparatus, according to the present invention, functions as astandardized restraint anchorage for connection with a child safety seatwithin a vehicle. The apparatus has the ability of strengthening theanchorage to resist forces due to the cantilever effect, whilemaintaining the criteria for the diameter at the striking surface of theanchorage without adding additional components and associated costs.

Another aspect of the present invention is to provide a latch wire andmethod for strengthening a child restraint anchorage system wherein thelegs are tapered such that they are wider at one end than at the other.

Another aspect of the present invention is to provide a latch wire andmethod for strengthening a child restraint anchorage system thatreinforces the latch wire without the aid of additional components.

Yet another aspect of the present invention is to provide a latch wireand method for strengthening a child restraint anchorage system thatreinforces the latch wire with minimal manufacturing time and cost.

Still yet another aspect of the present invention is to provide a latchwire and method for strengthening a child restraint anchorage systemwhich maintains the industry standard diameter across the retention zoneof the latch wire.

A further aspect of the present invention is to provide a latch wire andmethod for strengthening a child restraint anchorage system wherein theforming process begins by reducing a portion of a wire form larger thanthe industry standard diameter, or by expanding a portion of a wire formequivalent to the industry standard diameter.

Accordingly, a restraint anchorage for a child safety seat for anautomotive vehicle is provided. The restraint anchorage includes a crossmember, at least two mounting brackets attached to the cross member, andat least one pair of latch wires. The brackets secure the cross memberto the vehicle at a location behind a vehicle seat. Each latch wire isgenerally U-shaped having a pair of spatially separated legs joined atone end by a transverse latch bar. In operation, the child safety seatattaches to the transverse latch bar. Each leg includes a taperedportion and an end portion. The end portion is generally located at theend of the leg opposite the transverse latch bar. The tapered portionhas a base and a continuously expanding diameter. The diameter of thetapered portion at its narrowest end is approximately equal to thediameter of the transverse latch bar. The diameter of the taperedportion then expands from its narrowest end towards the base wherein thediameter is some amount greater than the diameter of the transverselatch bar. The tapered portion provides the latch wire withreinforcement for greater strength and rigidity under bending or tensileloads.

In a certain embodiment, the end portion of each leg of the latch wirespass through holes provided in the cross member. The length of the legsprotruding through holes provided in the cross member can be limited bya first collar or a shoulder disposed between the tapered portion andthe end portion of each leg. Once each pair of latch wires is mounted tothe cross member, a second collar engaging a surface of the cross memberon a side opposite the first collar can be formed in order to secure thelatch wire to the cross member to prevent it from being disengaged fromthe cross member by external forces. The first collar can be a collarhaving a diameter which extends radially outward a distance greater thanthe diameter of the end portion, or rather, the first collar can be ashoulder formed adjacent the base of the tapered portion which overhangsthe narrower end portion.

Correspondingly, a method for manufacturing a restraint anchorage for achild safety seat for an automotive vehicle is provided. The methodincludes providing a cross member and at least two mounting bracketsattached to the cross member. At least one pair of wire forms are alsoprovided to form at least one pair of latch wires. Each wire form isthen tapered in at least two locations, thereby forming two distincttapered portions. The tapering is performed such that each taperedportion is separated by a constant diameter transverse latch barportion. The U-shaped latch wire is then formed by providing a pair ofspaced legs separated at one end by the transverse latch bar portion.The latch wire undergoes a bending process to form the pair of spacedlegs. This is typically done in at least two spaced locations, one oneither side of the transverse latch bar portion.

The wire form can be tapered by reducing the diameter of a middleportion of the at least one pair of wire forms, or rather, the wire formcan be tapered by gradually expanding the diameter of selected locationsof the wire form. Generally, the wire form can be reduced by a swagingprocess. Alternatively, the wire form can be expanded by a cold headingprocess. Furthermore, the method includes forming a first collaradjacent each tapered portion of the latch wire. Upon attaching thelatch wire to the cross member, the first collar limits the amount oflegs protruding through holes provided in the cross member. Finally, asecond collar is formed on the latch wire on a side of the cross memberopposite the first collar to secure the latch wire to the cross member.

These and other aspects and advantages will become more apparent from areading of the detailed description in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side environmental view of a child safety seat secured to achild safety restraint anchorage system coupled to a passenger seatwithin a vehicle;

FIG. 2 is a perspective view of a child safety restraint anchorageincluding a plurality of latch wires;

FIG. 3 is a plan view of a latch wire according to a preferred aspect ofthe invention; and

FIG. 4 is a plan view of a latch wire according to an alternate aspectof the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

As required, detailed embodiments of the present invention are disclosedherein. However, it is to be understood that the disclosed embodimentsare merely exemplary of an invention that may be embodied in various andalternative forms. Therefore, specific functional details disclosedherein are not to be interpreted as limiting, but merely as arepresentative basis for the claims and/or as a representative basis forteaching one skilled in the art to variously employ the presentinvention.

Referring now to the Figures, an environmental view of the latch wireand restraint anchorage system of the present invention is illustratedin FIGS. 1 and 2. An anchorage 20 is fastened to the floor 22 of avehicle 10 with bolts 24, which extend through anchorage brackets 26.The anchorage 20 includes a plurality of latch wires 28 attached to across member 30. The anchorage 20 and latch wires 28 are positioned suchthat the latch wires 28 extend through a channel 31 formed between aseat cushion 32 and a backrest 34 of the vehicle passenger seat.

A child safety seat 36 is disposed on the seat of the vehicle 10. Incertain embodiments of the invention, a base 33 of the child safety seat36 rests on an upper surface 35 of the seat cushion 32 while a back 37of the child safety seat 36 rests against an outer surface 39 of thebackrest 34. The child safety seat 36 includes an extendable latchmechanism 38, which is adapted to latch onto one or more of theplurality of latch wires 28. The latch mechanism 38 may be spring loadedto retract and lock when the latch mechanism 38 engages the latch wire28 to pull the child safety seat 36 into place. Alternatively, latchmechanism 38 may be manually activated to engage and lock the childsafety seat 36 in position.

The anchorage 20 for the child seat safety restraint system according tothe present invention is shown in FIG. 2. Cross member 30 of anchorage20 is supported by multiple mounting brackets 26 attached to astructural member of the vehicle (not shown), such as the floor behindthe seat of the vehicle. It is understood that in many applications onlytwo mounting brackets may be required. The cross member 30 may be formedof steel, structural plastic, or carbon fiber material as a solid bar,plates or a tubular member, as shown in FIGS. 1 and 2. A plurality ofU-shaped latch wires 28 are attached to the cross member 30 atpredetermined locations.

The illustrated embodiment shows three pairs or sets of latch wires 28indicative of three possible mounting locations for a child safety seat36. These three locations are the left side of the seat, the right sideof the seat, and the center of the seat. It is understood that one ortwo sets of latch wires 28 may be attached to the cross member 30 ifdesired.

As shown in FIG. 1, the anchorage 20 is located behind the seat of thevehicle at a location such that the latch wires 28 extend forward in thechannel 31 between the seat cushion 32 and the backrest 34 of thevehicle seat. The anchorage 20 may include pivots or other attachments,such as pivot 40, permitting a portion of the backrest 34 to be foldeddown to provide access into the trunk area from the passengercompartment of the vehicle. Alternatively, pivot 40 may allow formovement of a foldable armrest. The mounting brackets 26 each have oneor more bolt holes 42 facilitating the bolting of the anchorage 20 tothe vehicle.

Referring now to FIG. 3, a first aspect of the invention illustratingthe latch wire 28 is shown. The latch wire 28 has a generally U-shapedconfiguration having a pair of spatially separated legs 44 joined at oneend by an integral transverse latch bar 46. The latch bar 46 provides acontinuous 6 mm diameter striking surface as required by the NationalHighway Traffic Safety Administration. The latch mechanism 38 of thechild safety seat (not shown) latches onto the latch bar 46 securing thechild safety seat to the vehicle.

Each leg 44 of the latch wire 28 includes a tapered portion 48 and anend portion 50. The tapered portion 48 subsumes a section of the leg 44nearest the latch bar 46, while the end portion 50 subsumes the sectionof the leg 44 opposite the latch bar 46. It is understood that taperedfor purposes of this invention means a section of the leg 44 that iswider at one end than at the other. The tapered portion 48 has a base 52designating the area of the tapered portion having the largest diameter.The diameter of the tapered portion 48 gradually decreases from the base52 as tapered portion 48 extends toward the latch bar 46. Ultimately,the tapered portion 48 achieves a minimum diameter approximately equalto that of the transverse latch bar 46. The tapered portion 48 may beconical in shape, as illustrated in FIGS. 3 and 4, or, alternatively,parabolic or some other similarly tapered shape.

The end portion 50 of leg 44 includes a generally continuous diameterextending from the base 52 towards the end of the leg 44 opposite thatof the latch bar 46. In a particular embodiment shown in FIG. 3, thediameter of end portion 50 is sized approximately equal to the base 52.Each leg 44 of latch wire 28 may include a rigid first collar 54 whichcan be formed by cold heading or any other process known in the art. Thefirst collar 54 may be disposed at the base 52 adjacent the taperedportion 48 and the end portion 50. First collar 54 is positioned formating engagement with the cross member (not shown) upon the attachmentof latch wire 28 to the cross member. Moreover, FIG. 3 illustrates anenlarged head forming a second collar 55 at the end of each leg 44.Second collar 55 secures the latch wire 28 to the cross member toprevent it from being disengaged from the cross member. Second collar 55is shown in phantom as it is not a part of latch wire 28 until latchwire 28 is secured to the cross member. Moreover, depending on themethod utilized for attaching latch wires 28 to the cross member, secondcollar 55 may be unnecessary.

A method for manufacturing the latch wire 28 in FIG. 3 is describedbelow. It is understood that other methods exist for achieving thetapered design provided by this invention, and that this invention isnot limited to the method detailed herein. A wire form having a desireddiameter is cut to a particular length. The diameter of the wire formmay be larger than the 6 mm industry standard, and is chosen towithstand the load-bearing forces applied to the latch wire 28 when inuse. In order to maintain the industry standard 6 mm diameter at theretention zone of the latch wire 28, i.e. the striking surface whichengages the latch mechanism 38, a portion of the wire form is reduced indiameter. Generally, the reducing step reduces the diameter of a middleportion of the wire form encompassing the transverse latch bar 46, downto the industry standard. The reduction is done gradually so as to formthe tapered portion 48 on either side of the latch bar portion 46. Theend portions 50 of legs 44 maintain their original diameter. The wireform can be reduced by any known processes in the art, such as swagingor machining, so long as the tapered portions 48 are formed on both endsof the latch bar portion 46.

If desired, collars 54 may be cold formed in a mechanical die press. Thecollars 54 may be formed adjacent the base 52 of the tapered portions48, or further down onto the end portions 50. In certain embodimentsshown, the collars 54 extend generally radially outward a distancegreater than the thickest portion of the legs 44 to limit the amount thelegs protrude through holes in the cross member 30 when the latch wire28 is attached thereto. Each collar 54 may be shaped in accordance witha mating surface of the cross member 30. For example, collar 54 mayprovide a curved surface for mating engagement with a round crossmember. Alternatively, collar 54 may provide a flat surface for matingengagement with a flat surface of the cross member 30.

Next, the wire form is bent to form the legs 44 of the latch wire 28 insuch a way as to provide a constant industry standard diameter retentionzone the entire length of latch bar 46. Moreover, the wire form can bebent to position the latch wire 28 into the channel 31 between the seatcushion 32 and backrest 34 when assembled in the vehicle. The wire formis typically bent in a series of operations as the wire form progressesthrough a transfer press system. However, it is fully contemplated thatthe wire form can be bent by other means. Moreover, it is understoodthat the bending operation can precede the reducing and/or collaringsteps in the process.

Finally, once the latch wire 28 is formed, it is then attached to thecross member 30. Any known method in the art for attaching can beutilized, such as welding or orbital peening, or the like. Theadvantages of manufacturing the latch wire 28 include providingreinforcement, strength and rigidity to the latch wire 28 under bendingand tensile loads, while maintaining the 6 mm industry standard diameterlatch bar 46. The larger diameter wire form found in the taperedportions 48 and the end portions 50 provide the necessary structuralreinforcement, while the reducing operation shapes the latch bar 46 tomeet the industry criteria.

Referring now to FIG. 4, an alternate aspect of the latch wire 28 of thelatch restraint and anchorage system of the present invention isillustrated. Similar elements retain the same reference numerals,whereas different elements are assigned different reference numerals.The latch wire 28 maintains all general features and advantagespreviously described. Here, latch wire 28 includes a pair of spatiallyseparated legs 44 joined at one end by an integral transverse latch bar46. The latch bar 46 provides the continuous 6 mm diameter strikingsurface standardized by the National Highway Traffic SafetyAdministration. The latch mechanism 38 of the child safety seat (notshown) latches onto the latch bar 46, securing the child safety seat tothe vehicle.

Each leg 44 of the latch wire 28 includes a tapered portion 48 and anend portion 50. It is understood that tapered for purposes of thisinvention means a section of the leg 44 that is wider at one end than atthe other. The tapered portion 48 has a base 52 designating the area ofthe tapered portion having the largest diameter. The tapered portion 48expands from near the latch bar 46 wherein the diameter is equivalent tothat of the latch bar 46 towards the base 52. The tapered portion 48 maybe conical or parabolic in shape.

The end portion 50 has a generally continuous diameter extending fromthe base 52 towards the end of the leg 44 opposite that of the latch bar46. In the particular embodiment shown in FIG. 4, the diameter of theend portion 50 is sized approximately equal to the 6 mm industrystandard of latch bar 46. Moreover, a shoulder 56 may be formed on eachleg 44 by the engagement of the end portion 50 to the base 52 usingmanufacturing methods described above. Shoulder 56 provides a surfacefor mating engagement with the cross member (not shown). As in FIG. 3,second collar 55 is illustrated in phantom to show that it may be formedafter latch wire 28 is attached to the cross member to prevent the latchwire 28 from being disengaged from the cross member.

The method of manufacturing the latch wire illustrated in FIG. 4 variesfrom the method outlined for the latch wire in FIG. 3. For example, thecontinuous diameter wire form is selected to meet the 6 mm industrystandard for the retention zone of the latch wire 28. The wire form isthen cut to the desired length. Since the wire form is selected to meetthe industry standard diameter, a reducing process is unnecessary.Rather, the tapered portions 48 are formed by an expanding process whichgradually expands the diameter of the wire form in preselected locationsfrom its original diameter to its end diameter represented by the base52. Such an expansion process generates a continuous integral coneshape, as shown in FIG. 4. It is understood that a continuous integralparaboloid may also be formed by expanding the wire form.

The tapered portions 48 may be formed by a cold heading process whereinthe wire form is sequentially driven into a mold cavity to expand thewire form. The number of steps required to obtain the desired shape ofthe tapered portion 48 may vary. Ultimately, tapering is achieved toprovide one end of the tapered portion 48 having a diameter greater thanthat of the other end. It is to be understood that any known process inthe art for expanding is fully within the scope of this invention. Theend portions 50 maintain the industry standard diameter of thepreselected wire form, and therefore are not expanded.

If desired, the wire form, once tapered, may undergo a collaring orshouldering process by which the shoulder 56 is formed from theintersection between the base 52 of the tapered portion 48 and the endportion 50. In a particular aspect of the invention, a smooth surfacecan be formed on the base 52 in a mechanical die press generating theshoulder 56. Shoulder 56 is shaped to correspond to a mating surface ofthe cross member 30. For example, shoulder 56 can be shaped tocorrespond to a round surface or a flat surface of the cross member 30.

Next, the wire form undergoes the bending operation similar to theprocess previously described above. The wire form is generally bent ator near the narrowest end of the tapered portion 48 forming the pair ofspatially separated legs 44, thereby forming the latch wire 28. The wireform may undergo additional bending as necessary to position the latchwire 28 into the channel 31 between the seat cushion 32 and backrest 34.Again, it is understood that the bending operation could precede theexpanding and/or collaring operation. Once the latch wire 28 is formed,it is attached to the cross member 30 to form the anchorage 20. Theattachment is achieved by any known method for attaching in the art,such as welding or orbital peening, or the like.

While embodiments of the invention have been illustrated and described,it is not intended that these embodiments illustrate and describe allpossible forms of the invention. Rather, the words used in thespecification are words of description rather than limitation, and it isunderstood that various changes may be made without departing from thespirit and scope of the invention.

1. A restraint anchorage for a child safety seat for an automotivevehicle comprising: a cross member; at least two mounting bracketsattached to said cross member for securing said cross member to thevehicle at a location behind the seat of the vehicle; and at least onepair of latch wires, each latch wire of said pair of latch wires havinga pair of spatially separated legs joined at one end by a transverselatch bar to which the child safety seat can be attached, each leghaving a tapered portion and an end portion opposite said transverselatch bar, the tapered portion having a base and a continuouslyexpanding diameter which expands from a diameter similar to saidtransverse latch bar to a larger diameter at the base of the taperedportion to provide greater strength and rigidity to each latch wireunder load.
 2. The restraint anchorage of claim 1 wherein said endportion of each leg passes through holes provided in the cross member.3. The restraint anchorage of claim 2 wherein the latch wire furthercomprises a first collar disposed between said tapered portion and saidend portion of each leg, the first collar limiting the length of saidlegs protruding through the holes provided in the cross member.
 4. Therestraint anchorage of claim 3 wherein the latch wire further comprisesa second collar engaging a surface of the cross member on a sideopposite the first collar to secure the latch wire to the cross memberand to prevent it from being disengaged from the cross member by a forceapplied to said transverse latch bar.
 5. A latch wire for a child safetyrestraint system retained by a cross member mounted to a vehicle behinda seat, the latch wire comprising: a transverse latch bar; and a pair ofspatially separated legs joined at one end by said transverse latch bar,each leg having a tapered portion and an end portion opposite saidtransverse latch bar, the tapered portion having a base and acontinuously expanding diameter which expands from a diameter similar tosaid transverse latch bar to a larger diameter at the base of thetapered portion to provide greater strength and rigidity to each latchwire under load, the end portion exposed for retention by the crossmember.
 6. The latch wire of claim 5 further comprising a first collardisposed between said tapered portion and said end portion of each leg,said first collar limiting the length of said legs protruding throughholes provided in the cross member.
 7. The latch wire of claim 6 furthercomprising a second collar engaging a surface of the cross member on aside opposite the first collar.
 8. The latch wire of claim 6 whereinsaid first collar extends radially outward a distance greater than thediameter of the end portion.
 9. The latch wire of claim 6 wherein saidfirst collar is a shoulder adjacent the base of the tapered portion. 10.The latch wire of claim 5 wherein said end portions of the legs are bentto extend into a channel between a seat cushion and a backrest of theseat of the vehicle.